Distillation of hydrocarbon oils



May 5, 1936- G. PAULUS ET AL DISTILLATION p1 HYDROCARBON OILS 2 Sheets-Sheet 1 Filed Oct. 16, 1930 M y 1936- M. G.- PAULUS El AL DISTILLATION 0F HYDROCARBON- OILS Riled Oct'. 16,1930 2 Sheets-Sheet 2' Patented May 5, 1936 UNITED STATES 2,039,919 r 'nrsrnmrron or nmnocannorr oms Max G. Paulus and Andrew E. Thompson, Casper, Wyo., assignors to Standard Oil Company,

Whitin g, Ind., a corporation of Indiana Application October s, 1930, Serial No. 489,197 3 Claims. (01. 196-108) The present invention relates to the distillation of hydrocarbon oils, and refers more particularly to certain improvements-in connection with distillation processes carried out by means of the, well-known shell-type of still.

The invention will be fully understood by reference to the following detailed description 11- lustrated by the accompanying drawings, in which:

Figure 1 illustrates, partly in section and in part diagrammatically, apparatus suitable for carrying out the distillation of hydrocarbon oils and embodying structure for employing the present invention in" connection therewith;

1 Fig. 2 is an enlarged vertical sectional view of a sleeve surrounding the pipe leading from the shell still to the lower tube header;

Fig. 3 is a side elevational view of the same, and

Fig. 4 is a top plan view of the sleeve.

Referring more particularly to Fig. 1, the numeral 5 indicates a suitable oil container, preferably a horizontal, cylindrical shell or still .adapted to withstand high internal pressure and to contain a substantial body of oil undergoing treatment. The shell or still 5 is mounted upon a suitable furnace setting 6, andis protected from the direct heat therefrom. Within the furnace setting there is provided a large number or bank of inclined tubes 1, the lower ends .of which communicate with a lower header 8 and the upper ends of which communicate with an upper header 9.. The lower header 8 communicates with a vertical pipe l0 which extends upwardly out of the furnace setting through the wall of the shell 5 and for a short distance thereinto. The upper end of this tube or pipe l0 forms a seat for a closure member ll mounted on the stem of a rod l2 threaded through'a'boss. l3 on the upper part of the shell 5, the rod being operated by a hand wheel II. It is readily apparent that, by operation of the rodl2, the upper end of. the tube or pipe Ill mayibe closed to prevent communication with the contents of the shell 5 or may be opened to permi free communication therewith.

The upper header 9 likewise communicates with an upright pipe or tube l5 which enters therein is returned by the pipe l9 t 0 the interior of the pipe I0 in the upper portion thereof. Vapors uncondensed in the reflux condenser l8 are discharged to a suitable final condenser and pressure controlling means, such as are com- I monly employed in the art and are not shown herein.

From a point above the bottom of the shell 5,

a conduit 20-, provided with a pressure release plates 26 of any suitable form, or other suitable means for preventing entrainment of unvaporized liquids by the vapors leaving the drum. From the upper portion of the drum, the vapor Within conduit 21 leads vapors to the lower portion of a column or tower 28, illustrated diagrammatically as a bubble tower. The plates in the tower 28 may be of any desired form.

At a suitable intermediate point in the tower 28, the feed pipe 29 enters and may be employed for the supply of a hydrocarbon oil cooling medium or for the supply of fresh oil fed to the unit.

A second supply pipe 30 enters the upper portion of the tower and may be employed for supplying thereto a cooling medium of a lower range of boiling points, such as, for example, a condensate from the vapors evolved from the tower 28. From the upper portion of the tower, a vapor conduit 3| leads to anysuitable condensing means (not shown).

Condensate formed in the fractionating column or tower 28 and collected in the base thereof is withdrawn through valved pipe 32 and forced by pump 33 through the valved pipe 34 to an intermediate point in the fractionating column I I, from which it passes, together with reflux V condensate through pipe I! into the large pip ll extending from the lower header I in the furnace into the still 5.

From the base of the drum 2|. unvaporized-oil is discharged through the valved pipe 38 leading to a tar cooler or heat exchanger ll, from which the cooled 'unvaporized oil or tar is discharged through the line 42.

The bottom wall of the still 5 is provided with a valved line 31, whereby the still may be drained. A vapor draw-off line 38, provided with a pressure reducing valve 39, leads from the top of the still i to the line 20 at a point beyond the reducing valve 2| therein, whereby vapors may be admixed with the heavy oil or tar withdrawn through within the shell 5 and surrounds the pipe Ill. The upper end of the sleeve 46 extends a substantial distance above the mouth of pipe l0 and the lower end extends a substantial distance below the mouth of pipe ill but is spaced somewhat above the bottom wall of the shell 5.

, The'inner diameter of the sleeve" is substantially greater than the exterior diameter of the pipe Ill so that an annular space is provided therebetween, as shown more clearly in Fig. 2. The sleeve is supported at its lower end by a plurality of legs 41 secured to the bottom wall of the shell 5.

The lowerportion ll of the sleeve 46 is formed as a single unitary cylindrical section and the upper portion of the sleeve is formed by a pair of semi-cylindrical sections 49, each of which is hinged to the lower portion 48 by means of a hinge 50. By means of this structure, the upper portion of the sleeve may be opened for cleaning purposes, the two semi-cylindrical sections 18 being movable to the positions shown by dotted lines in Fig. 2. The sections 49 may be locked into closely fitting engagement to form a closed cylinder in any suitable manner, for example, by means of ears 5|, one of which fits just below the other, whereby a pin 52 may be passed through corresponding registering holes therein, as shown more clearly in Figs. 3 and 4. The lower cylinticular bearing on'one particular stage or phase of operation employedin these processes- It, is, to be clearly understood, however, that the present invention is not limited to the particular processes described in these applications, and

may be employed in connection with any, still wherein all, or part, of the heating of oil therein is accomplished by withdrawing portions of the oil from a chamber, subjecting the withdrawn oil to heating and returningit to the chamber, or in which a continuous flow of oil is'maintained, "in part, by withdrawal of oil from the shell. The invention may be employed in connection with either cracking or non-cracking distillation operations.

\ In carrying out the processes described in the above applications, it is desirable to initially charge the still 5 in a level slightly above the tops a of pipes I I and I5, said pipes, the headers I and charge is about 8000 gallons. 'The rod I2 is operated to open the upper end of pipe ll, so that the entire contents ofthe still may be circulated through the inclined tubes I and brought up to cracking temperature by the furnace heat applied to the said tubes 1.

During the above operation, there is a marked tendency of the oil to stratify in relatively hot and cool layers, there generally always being a cool layer along the bottom of theshell 5 and below the tops of pipes l0 and I5. This condition is apparently due to the fact that the cold oil is trapped below the mouth of pipe I 0 and the outlet of pipe l5. This condition causes an undesirable temperature differential between the sides and the bottom of the shell 5 causing the walls of the shell to be subjected to substantial stress and tension, a condition highly dangerous due to the high temperature and pressure conditions ordinarily employed. When heating a cold batch of oil to cracking temperature the temperature differential between the side wallsand bottom of the shell has been found to be as high as 350 F.

The top of the sleeve 46 extends above the level of the oil body and thus causes the lower layer of cooler oil to be drawn into the pipe l0 and passed to the tubes I wherein it is heated so that the temperature of the oil body is thus rendered more uniform. WVith the sleeve 46 the temperature diiferential between the metal side walls and bottom wall is from 200 to 300 F. less than y when it is not present, averaging between 60 and 80 F.

When the still has reached the desired temperature, the oil level may be raised to a point above the top of the sleeve IG and oil may flow through the top end of the sleeve and into the pipe in, so that the still win operate in substantially the same manner as it would without the sleeve. In the event it is necesary to remove coke or other sediment from within the sleeve, the same may be easily accomplished by unlatching the lugs 5| and pivoting the semi-cylindrical sections 49 to the position shown by dotted lines in Fig. 2.

It will be understood that the specific details of apparatus and method hereinbefore set forth are for the purpose of illustration, and are not intended to be regarded as limitations upon the scope of the invention, except as contained in the following claims.

We claim:

1. Apparatus for effecting distillation of hydrocarbon oils, comprising a still chamber, a conduit for conducting oil from said still chamber, said conduit having a portion projecting into the still chamber at a point above the bottom thereof and below the oil level therein. and a tubular sleeve surrounding the projecting portion of said conduit in spaced relationship thereto, said sleeve extending from a point substantially below the mouth of said conduit to a point substantially above the mouth of said conduit, the upper portion 'of said sleeve comprising a pair of hinged separable members.

2. Apparatus for eifecting distillation of hydrocarbon oils, comprising a still chamber, a conduit for withdrawing oil from said still chamber, said conduit protruding upwardly from the bottom wall of said still chamber to a point intermediate the top and bottom walls thereof and below the oil level therein, a sleeve surroimding the protrading portion of said first conduit in a spaced relationship thereto, said sleeve being open at both the upper and lower ends and extending from a; point below the mouth of said conduit to a point above the oil level in the still chamber in 'the initial stages of operation, whereby'oil-below the mouth of said conduit in the mouth of said conduit through the opening in the lower end of said sleeve, and means for supplying heated oil to said still chamber at a point remote from said conduit to raise the level of oil therein after the initial stages of operation,-whereby the oil reaches a level at least as high as the opening in the upper end of said sleeve and flows therethrough to the mouthof said conduit.

3. Apparatus for efiecting distillation of hydrocarbon oils comprising a still chamber,'a conduit for withdrawing oil from said still chamber and discharging it into a heated zone, said conduit protruding upwardly from the bottom wall of the still chamber to a point intermediate the top and bottom walls thereof and below the oil level therein, a second conduit for returning the heated oil from said heated zone to said still chamber zone at a point substantially remote iromthe mouth of said first named conduit, a sleeve surrounding said first conduit in spaced relationship thereto, said sleeve being open at both the upper and lower ends and extending from a point substantially below the mouth of said first conduit to a point substantially above the mouth of said conduit and the oil level in said still in the initial stages of operation, whereby after the initial stages of operation, whereby the oil reaches a level at least as high as the opening in the upper end of said sleeve and flows therethrough to the mouth of said conduit.

MAX G. PAULUS.

ANDREW E. THOMPSON. 

